I know the counters are slightly off with the trophies, but do I need to melee another 5k enemies for it to finally trigger? Stats are showing 5k enemies killed to melee, and feel like I've gone through another 5k already.
The Deed and trophy are not linked in the first place so the completed Heroic Deed won't affect your trophy's progress even if they count the same.
Relentless Slaughter is working now as I understand, friend got it this morning, but we don’t way more then 5 000 kills so far, since deed was closed long time ago.
We are currently re-checking if the applied fixes do work or not. Some players have doubts but we could not yet confirm this. You can expect a fix in this regard if it is still not working.